A recently published study compared warning and withdrawal rates for drugs released before and after the FDA began expediting drug approvals through PDUFA and found that drugs released after PDUFA passed were more likely to be withdrawn or have a black box warning.
Researchers from Cambridge Health Alliance/Harvard Medical School, Boston Medical Center/Boston University School of Medicine, City University of New York School of Public Health, and Public Citizen published the study in the August issue of Health Affairs.
The study compared warning and withdrawal rates for drugs released before and after 1992, when the approval process for medications changed with the passing of the Prescription Drug User Fee Act. PDUFA allows the FDA to collect fees to expedite drug approvals; since the law’s enactment, the average drug approval time for all drugs has lessened from 34 months to 16 months.
The researchers discovered that drugs released after PDUFA passed were more likely to be withdrawn or have a black box warning, with 26.7 percent of these drugs receiving such a warning compared to 21.2 percent in the pre-PDUFA drugs that underwent the longer approval process. Half of all black box warnings appeared after a drug had been on the market for 12 years, and safety withdrawals have occurred as late as 30 years after a drug's initial release.
The study authors suggest that the expedited process may have led to the approval of drugs before they could be adequately evaluated for safety issues.
Industry blogger John Mack (aka "PharmaGuy") pointed out that even as PDUFA fees increased dramatically after 2001/2002, the number of warning letters issued remained pretty flat, which indicates that PDUFA (and cash) had no effect. Read the Pharma Guy's slightly different take on the study